Publications de Wolfgang Harbich

Cluster Catalysis with Lattice Oxygen: Tracing Oxygen Transport from a Magnetite (001) Support onto Small Pt Clusters

Wolfgang Harbich, Giulia Elisabetta Pacchioni, Ke Zhang

Oxidation catalysis on reducible oxide-supported small metal clusters often involves lattice oxygen. The present work aims at differentiating whether the reaction takes place at the cluster/support interface or on the cluster. To that purpose, we trace the ...

AMER CHEMICAL SOC2021

Optical properties of size selected neutral Ag clusters: electronic shell structures and the surface plasmon resonance

Harald Brune, Wolfgang Harbich, Chongqi Yu

We present optical absorption spectra from the ultraviolet to the visible for size selected neutral Ag-n clusters (n = 5-120) embedded in solid Ne. We compare the spectra to time-dependent density functional calculations (TDDFT) that address the influence ...

ROYAL SOC CHEMISTRY2018

Intense fluorescence of Au-20

Harald Brune, Wolfgang Harbich, Chongqi Yu

Ligand-protected Au clusters are non-bleaching fluorescence markers in bio- and medical applications. Here we show that their fluorescence can be an intrinsic property of the Au cluster itself. We find a very intense and sharp fluorescence peak located at ...

American Institute of Physics2017

Erratum: “Intense fluorescence of Au20”

Harald Brune, Wolfgang Harbich, Chongqi Yu

American Institute of Physics2017

Growth of palladium nanoparticles on nanostructured highly ordered pyrolytic graphite

Wolfgang Harbich

We report on the growth of palladium nanoparticles on the basal plane of as-cleaved highly oriented pyrolytic graphite (HOPG) samples, and on CO2 ion sputtered nanostructured HOPG surfaces. The morphology of Pd nanostructures grown at room temperature is i ...

Wiley-Blackwell2015

Reaction-Induced Cluster Ripening and Initial Size-Dependent Reaction Rates for CO Oxidation on Pt-n/TiO2(110)-(1x1)

Harald Brune, Wolfgang Harbich, Simon Bonanni

We determined the CO oxidation rates for size-selected Pt-n (n is an element of {3,7,10}) clusters deposited onto TiO2(110). In addition, we investigated the cluster morphologies and their mean sizes before and after the reaction. While the clusters are fa ...

American Chemical Society2014

Effect of the TiO2 Reduction State on the Catalytic CO Oxidation on Deposited Size-Selected Pt Clusters

Harald Brune, Wolfgang Harbich, Simon Bonanni

The catalytic activity of deposited Pt-7 clusters has been studied as a function of the reduction state of the TiO2(110)-(1 x 1) support for the CO oxidation reaction. While a slightly reduced support gives rise to a high catalytic activity of the adpartic ...

2012

Spectroscopy of 3, 4, 9, 10-perylenetetracarboxylic dianhydride (PTCDA) attached to rare gas samples: Clusters vs. bulk matrices. I. Absorption spectroscopy

Wolfgang Harbich, Alexandre Rydlo, Matthieu Dvorak, Stefan Minniberger

The interaction between 3, 4, 9, 10-perylenetetracarboxylic dianhydride (PTCDA) and rare gas or para-hydrogen samples is studied by means of laser-induced fluorescence excitation spectroscopy. The comparison between spectra of PTCDA embedded in a neon matr ...

American Institute of Physics2012

Spectroscopy of 3, 4, 9, 10-perylenetetracarboxylic dianhydride (PTCDA) attached to rare gas samples: Clusters vs. bulk matrices. II. Fluorescence emission spectroscopy

Wolfgang Harbich, Alexandre Rydlo, Matthieu Dvorak, Stefan Minniberger

The interaction between 3, 4, 9, 10-perylenetetracarboxylic dianhydride (PTCDA) molecules and solid rare gas samples is studied by means of fluorescence emission spectroscopy. Laser-excited PTCDA-doped large argon, neon, and para-hydrogen clusters along wi ...

American Institute of Physics2012

Electrochemical promotion of CO combustion over non-percolated Pt particles supported on YSZ using a novel bipolar configuration

Christos Comninellis, Wolfgang Harbich, György Foti, Michael Hugentobler, Chun Xia

The electrochemical promotion of CO combustion over nano-dispersed Platinum particles supported on yttria stabilized zirconia (YSZ) is investigated at 300 degrees C under high vacuum conditions. By polarizing the nanoparticles, we were able to enhance the ...

Elsevier2011

UV-visible absorption of small gold clusters in neon: Au-n (n=1-5 and 7-9)

Wolfgang Harbich, Alexandre Rydlo, Sylvain Lecoultre

We present optical absorption spectra in the UV-visible range (1.5 eV < E < 6 eV) for mass selected neutral gold clusters Au-n (n = 1-5 and 7-9) embedded in solid Ne at 7 K. The experimental spectra are compared with time-dependent density functional calcu ...

American Institute of Physics2011

Optical absorption of small copper clusters in neon: Cu-n, (n=1-9)

Wolfgang Harbich, Alexandre Rydlo, Sylvain Lecoultre

We present optical absorption spectra in the UV-visible range (1.6 eV < omega < 5.5 eV) of mass selected neutral copper clusters Cu-n(n = 1-9) embedded in a solid neon matrix at 7 K. The atom and the dimer have already been measured in neon ma ...

American Institute of Physics2011

Ultraviolet-visible absorption of small silver clusters in neon: Ag-n (n=1-9)

Wolfgang Harbich, Alexandre Rydlo, Sylvain Lecoultre

We present optical absorption and fluorescence spectra in the UV-visible range of size selected neutral Ag-n clusters (n = 1-9) in solid neon. Rich and detailed optical spectra are found with linewidths as small as 50 meV. These spectra are compared to tim ...

American Institute of Physics2011

Solid electrochemical mass spectrometry (SEMS) for investigation of supported metal catalysts under high vacuum

Christos Comninellis, Wolfgang Harbich, Cyril Falgairette, Chun Xia

A new experimental set-up, coupling electrochemistry and mass spectroscopic techniques, for the investigation of a solid electrochemical cell under high vacuum conditions (HV) is presented. Two configurations are realized allowing the investigation of both ...

Springer Netherlands2010

Quantifying electrochemical promotion of induced bipolar Pt particles supported on YSZ

Christos Comninellis, Wolfgang Harbich, Michael Hugentobler, Chun Xia, Yuehui Li

Electrochemical promotion (EP) of CO oxidation is shown for the first time on induced bipolar Pt particles supported on yttria-stabilized zirconia (YSZ). These Pt particles are formed by sputter deposition of high-purity Pt metal followed by sintering. Con ...

Elsevier2010

Investigation of the Pt/YSZ interface at low oxygen partial pressure by solid electrochemical mass spectroscopy under high vacuum conditions

Christos Comninellis, Wolfgang Harbich, György Foti, Cyril Falgairette, Chun Xia

The Pt/YSZ interface was investigated at low oxygen partial pressure under high vacuum (HV) conditions at 400 A degrees C. Two different electrochemical techniques were coupled to mass spectrometric gas analysis using a new solid electrochemical mass spect ...

Springer Netherlands2010

Electrochemically stable gold nanoclusters in HOPG nanopits

Wolfgang Harbich, György Foti, Mériadec Limat, Michael Hugentobler

2009

Gold dimer in neon: an absorption and fluorescence study

Wolfgang Harbich, Alexandre Rydlo, Sylvain Lecoultre

We report for the first time the absorption and fluorescence spectra of gold dimers in a neon matrix. The dimer absorption spectra show the A←X transition predicted from measurements in the gas phase and not observed so far in a matrix, as well as the so-c ...

2009

Electronic excitations induced by the impact of coinage metal ions and clusters on a rare gas matrix: neutralization and luminescence

Christoph Sieber, Wolfgang Harbich

Low energy collisions of atomic ions and cluster ions with rare gas covered metal substrates can lead to strong light emission which is element and size specific. Instead of a direct energy transfer into the electronic system of the cluster the observed em ...

2007

Collision-induced luminescence from the impact of ions and cluster ions on solid rare gases

Christoph Sieber, Wolfgang Harbich

Light emission during the collision of ions and cluster ions on a metal surface covered by rare gas matrices of variable thickness is reported. The light intensity as a function of distance from the metal surface follows the classical image dipole theory. ...

Elsevier2006